Method and stereoscopic optical apparatus for determining the roughness of the surfaces of machined parts

ABSTRACT

A method and apparatus for stereoscopically determining the roughness of the surfaces of machined parts. A stereoscopic viewing means is provided for presenting to the operator stereoscopic images of the surface of a machined part, and simultaneously stereoscopic images of gauge surfaces, so that a comparison of the surface of the machined part with the surface of the gauges can be made. A projecting means is provided for projecting to the stereoscopic viewing means an image of the machined surface which is to be checked, while a pair of projecting means coact with a pair of gauges to project separate images thereof respectively to a pair of ocular means of the stereoscopic viewing means so that in this way images of the gauges are provided for the operator to be viewed simultaneously with the stereoscopic images of the surface of the machined part.

United States Patent Inventors Liviu Iliescu;

Ion Dragos, Bucharest, Romania 678,805

Oct. 30, 1967 May 25, 1971 Ministerul Industriei Constructilior DeMasini Bucharest, Romania Appi. No. Filed Patented Assignee METHOD ANDSTEREOSCOPIC OPTICAL APPARATUS FOR DETERMINING THE ROUGHNESS OF THESURFACES 0F MACHINED PARTS 1 Claim, 3 Drawing Figs.

Primary Examiner-Ronald L. Wibert Assistant Examiner-J RothenbergAttorney-Arthur O. Klein ABSTRACT: A method and apparatus forstereoscopically determining the roughness of the surfaces of machinedparts. A stereoscopic viewing means is provided for presenting to theoperator stereoscopic images of the surface of a machined part, andsimultaneously stereoscopic images of gauge surfaces, so that acomparison of the surface of the machined part with the surface of thegauges can be made. A projecting means is provided for projecting to thestereoscopic viewing means an image of the machined surface which is tobe checked, while a pair of projecting means coact with a pair of gaugesto project separate images thereof respectively to a pair of ocularmeans of the stereoscopic viewing means so that in this way images ofthe gauges are provided for the operator to be viewed simultaneouslywith the stereoscopic images of the surface of the machined part.

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METHOD AND STEREOSCOPIC OPTICAL APPARATUS FOR DETERMINING THEROUGI-INESS OF THE SURFACES OF MACHINED PARTS This invention is relatedto a method and to a stereoscopic optical apparatus for determining bycomparison the roughness of machined surfaces.

The determination of the roughness of surfaces by comparing them withmetallic standards, using a stereoscopic optical comparator is alreadyknown. The first image given by the studied surface is formed in thefield of the oculars, and the second image of a metallic standard gaugeis superposed upon the first image, allowing the direct comparison ofthe microunevennesses from a zone of the surface of the part with thesurface of the standard gauge.

The disadvantage of known stereoscopic optical apparatus, working withthe method of comparison with metallic standard gauges, consists in thefact, that, for determining the roughness of the surfaces of the parts,a very large number of metallic standard gauges are necessary forstereoscopic coincidence; such gauges are difficult to manufacture andto maintain.

Also the measuring of the microunevennesses of the surfaces of machinedparts with the aid of a stereoscopic optical apparatus is known.Measuring the height of each microunevenness is carried out with the aidof a mobile indicator and a fixed one, the indicators being instereoscopic coincidence and adjustable from outside. An essentialdrawback of the known apparatus and method, working with the method ofmeasuring point by point, consists in the fact that, for measuring theroughness of the surface of the part, a large number of measurements,readings, and successive adjustments are necessary which, due to thesubjectivity of the operator, leads to erroneous measurements.

This invention eliminates the above shown disadvantages in detenniningthe roughness of surfaces of a machined part; it compares the surfacewith photographed standard gauges (diapositive white-black or colored),which are mounted on a single frame in stereoscopic coincidence, using astereoscopic apparatus.

Metallic standard gauges may be used instead of photographs of standardgauges.

The stereoscopic optical apparatus according to the invention, whichcorresponds to the above-described method, consists of two doubleoptical systems, a first one to observe the surface of the part, theroughness of which is measured, and the other, second one to observe thephotographed standard gauge; a device to hold the photographed standardgauges; a mirror which is mounted under the first optical system forselectively observing the roughness of inside surfaces or of verticalsurfaces. It is also possible to employ instead of the second systemanother optical system equivalent to the first, which compares thesurfaces with metallic standard gauges, all

' systems being double for each eye, obtaining in this way astereoscopic image'of the studied surface.

There is described herein below an example of an embodiment of theinvention in conjunction with the FIGS. 1, 2, and 3 which represent:

FIG. I is a schematic representation of the stereoscopic apparatus forcomparison with photographed standard gauges;

FIG. 2 is a schematic representation of the device for fixing thephotographed standard gauges; and

FIG. 3 is a schematic representation of the stereoscopic apparatus forcomparison with metallic standard gauges.

The stereoscopic optical apparatus for determining the roughness ofmachined surfaces by comparing these with photographed standard gauges(FIG. 1), according to the invention, consists of an outfit 1, composedof an incandescent lamp 2 and lenses 3 for illuminating the surface ofpart a with a beam of parallel rays. An objective formed by lenses 4,projects the image of the observed part into one half b of the field ofboth oculars 5,5 which form two optical systems A B for each eye,consisting each of a prism 6 and lenses 7 and 8. For illuminating thephotographed standard gauges two projectors 9 are used, comprising anincandescent lamp l and a white milky glass 11, used for uniformilluminating of the transparencies in the form of white-black or coloreddiapositives, mounted in stereoscopic coincidence in a fixing device 12.A double objective 13 projects, by means of a prism 14, an image of thephotographed standard gauges in the other half b of the field of theoculars 5, 5', forming two optical systems C, D for obtaining thestereoscopic image. For determining the roughness of inside or verticalsurfaces a, a mirror 15 mobile in all directions, is mounted under theobjective 4.

The supporting device 12 for the photographed standard gauges, accordingto the invention (FIG. 2), consists of a frame 16, having lateralgrooves c for correct positioning of each pair of standard gauges infront of the objectives 13, in which some photographed standard gauges17 are fixed (white-black or colored diapositives) in stereoscopiccoincidence.

The determination of the roughness of machined surfaces by comparingthem with photographed standard gauges, according to the invention, isdone by taking aim simultaneously at the machined part and at thephotographed standard, gauge, comparing by superposing the images, andchoosing the next class of roughness according to the standard gauges,by moving the frame 16 in front of the objectives 13.

The device for comparison with metallic standard gauges (FIG. 3,) whichcan be adapted, instead of the device for comparison with photographedstandard gauges, to the stereoscopic optical apparatus, according to theinvention, consists of a projector 18 for illuminating the surfaces ofthe standard gauges, comprising an incandescent lamp l9 and some lenses20, which project a fascicle of parallel rays upon metallic standardgauges 21 in stereoscopic coincidence. An objective, formed by thelenses 22, projects the image of the surface of the metallic standardgauges 21 in the other half b of the field of the oculars 5, 5, by meansof prisms 23 and 24. The whole device forms a double optical system foreach eye E,F.

The determination by comparison with metallic standard gauges is alsoachieved by simultaneously taking aim upon the part and the standardgauge, choosing by comparison the next class of roughness, changing eachpair of standard gauges which are not mounted on a frame in front of theobjective 21.

The method and the stereoscopic optical apparatus, according to theinvention, present the following advantages:

they allow the roughness of internal and external surfaces in eitherhorizontal or vertical planes to be determined;

they determine the roughness of the surfaces of machined parts, bycomparison with photographed standard gauges (white-black or coloreddiapositives) in a manner which is easy to handle and to maintain;

metallic standard gauges in stereoscopic coincidence can also beutilized.

Although the invention is illustrated and described with reference to aplurality of preferred embodiments thereof, it is to be expresslyunderstood that it is in no way limited to the disclosure of such aplurality of preferred embodiments, but is capable of numerousmodifications within the scope of the appended claim.

We claim:

1. In a device for determining the roughness of the surface of a machinepart, stereoscopic viewing means having a pair of oculars for providinga pair of stereoscopic viewing fields, a single projecting meanscoacting with said stereoscopic viewing means for providing the latterin said fields thereof with images of the surface of a machined part,and a pair of additional projecting means coacting with said viewingmeans for respectively providing in the viewing fields thereof images ofa pair of gauges to be compared with the images of the surfaces of themachine part, said single projecting means including a projectingobjective having an optical axis symmetrically situated between theoptical axes of said oculars of said viewing means, said pair ofadditional projecting means respectively including objectivesrespectively having parallel optical axes extending parallel to theoptical axis of said objective of said.

single projecting means with the optical axes of said oculars situatedbetween the optical axes of said objectives of said additionalprojecting means.

